Mechanical Performance and Microstructure of Geopolymer Prepared from High Calcium Fly Ash

Title: Mechanical Performance and Microstructure of Geopolymer Prepared from High Calcium Fly Ash
Author(s): Xiaolu GUO, Huisheng SHI
Paper category : conference
Book title: 2nd International Conference on Waste Engineering and Management - ICWEM 2010
Editor(s): J.Zh. Xiao, Y. Zhang, M.S. Cheung and Reuben P. K. Chu
Print-ISBN: 978-2-35158-102-5
e-ISBN: 978-2-35158-103-2
Publisher: RILEM Publications SARL
Publication year: 2010
Pages: 244 - 252
Total Pages: 9
Nb references: 15
Language: English

Abstract: Geopolymers prepared from a high calcium fly ash (CFA) and a mixed alkali activator of sodium hydroxide and sodium silicate solution were investigated. A high compressive strength was obtained when the modulus of the activator viz., molar ratio of SiO2/Na2O was 1.5, and the proper content of this activator as evaluated by the proportion of Na2O to CFA was 10 %. The compressive strength of these samples was 63.4 MPa when they were cured at 75 oC for 8 h followed by curing at 23 oC for 28 d. In FTIR spectroscopy, the main peaks at 1036 and 1400 cm-1 have been attributed to asymmetric stretching of Al-O/Si-O bonds, while those at 747 cm-1 are due to the Si-O-Si/Si-O-Al bending band. The main geopolymeric gel and calicum silicate hydrate (C-S-H) gel co-exist and bond some remaining unreacted CFA spheres as observed in XRD and SEM. The presence of gismondine (zeolite) was also observed in the XRD pattern.

Online publication: 2011-01-25
Publication type : full_text
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